BRZ/86 stopping distance

[venturaII]

Originally Posted by Stephen W.

However, if you were to take two BRZ’s, one with standard brakes and the other with the Brembo brakes given everything else is equal, (the same make/model/size/compound of tire, time of day, road surface etc.) the Brembo car WILL stop in a shorter distance.

Explain this please.

[Ultramaroon]

Originally Posted by Stephen W.

Standard brakes use a sliding or floating style caliper whereby piston(s) are only on one side. When force is applied it pushes the brake pad against one side of the rotor. Continued force will cause the caliper to pull the opposite pad into contact with the other side of the rotor.

This is absolutely incorrect. If this were the case it wouldn't be called a "floating" caliper. It would be called a rusted, sticking caliper.

[venturaII]

If ABS is triggered, then the brakes are providing more force than the tires can put to the ground. Any additional braking force beyond that is pointless, and does not translate to shorter braking distances. The brake configuration is irrelevant.

[Stang70Fastback]

Originally Posted by venturaII

If ABS is triggered.

God-damned liberal ABS systems are so easily-triggered these days.

[Dadillac]

Alright I think I got it. I have never had a BBK on a car before. And as of yet have never autocrossed. I just thought it very strange that this car doesn't have published stopping distances for the two brake systems. Usually magazines post a lot of info when they test a car. 0-60, 60-0, skid pad, etc. Not too much info out there


Don

[Grady]

Originally Posted by Dadillac

Alright I think I got it. I have never had a BBK on a car before. And as of yet have never autocrossed. I just thought it very strange that this car doesn't have published stopping distances for the two brake systems. Usually magazines post a lot of info when they test a car. 0-60, 60-0, skid pad, etc. Not too much info out there


Don

Has anyone tried to google “BRZ stoping distance”?

I got 116 and 120ft.

FT86Speedfactory has pads that will stop the car faster.

Although the cars had different tires. You can hear the tires loosing traction in the fist stop. The shorter stop the tires had more grip and you do not hear them sliding.

[churchx]

IF one can lock till wheels engagement of ABS on tires one run, then different pads or different brake kit will not stop faster.
Grippier tires (with any pads, if they are sufficient) is only way to decrease stopping distance.

Only way stopping distances can be improved with different BBK or different pad choice (eg. staggered), is if/when factory brake bias has became not optimal (in case of eg. heavy aftermarket aero bits with lot of extra downforce on one end of car), but as many do aero changes to both ends, it also is not that common setup case.
Other way BBKs or pads can improve stopping is only for cases where OE setup starts failing due overabuse, eg. if one overheats brakes during track use and they faded. Again, that's not applicable for daily driving/normal braking efficiency/distances.

Tires are main bit (and in this video too). Brakes, if you can brake enough with either setup to lock, won't change. You just press pedal less with higher friction brake setup.
As for THE most grip to get from same tire, on dry tarmac it's usually peaks near almost slipping (why treshold braking sometimes can be more effective then ABS) and then after tire slips, grip falls off quick. Less peaky on loose grip pavement (wet/snow/ice/gravel).

[Stephen W.]

Originally Posted by venturaII

Explain this please.

If you understand (and accept) the logic of my first post than I shouldn’t have to explain anything. If you do not than read on.
Switching from stock to high performance pads will decrease the stopping distance of any vehicle, correct? There are lots of articles, videos and threads (some on this forum) that explain this. FT86 Speedfactory shows their HP+ pads giving an average of two car lengths, 60 – 0 over stock pads. That’s because stock pads are a compromise, longevity over stopping distance. High Performance pads do the opposite by wearing faster in order to achieve better stopping performance.(No, not the above video of the red vs. silver cars although, if you read their report it does mention Motor Trends stock distance.)
So think of it this way, Brembo brakes are just bigger versions of high performance pads with better calipers.

[Stephen W.]

Originally Posted by Ultramaroon

This is absolutely incorrect. If this were the case it wouldn't be called a "floating" caliper. It would be called a rusted, sticking caliper.

So, are you saying that my statement is completely, totally, utterly, entirely, wholly, thoroughly and unreservedly not in accordance with fact? Is that your position?
Please explain what the error is.

[venturaII]

As has already been explained several times above, the TIRES are what stop the car, not the brakes. If your stock brakes are able to lock the tires up (and they are fully capable of doing that), then the tires are what determine braking distance; going to bigger brakes does nothing because the tires are already being slowed down faster than the car is capable of decelerating. You can't make the tires lock up 'more' and expect stopping distance to change at all. 2800 pounds on tire brand/size 'X' is only going to be capable of stopping in a certain distance. Going to sticker or larger tires, on the other hand, WILL improve your braking distance, at least to the point where they are able to overpower your brakes. Only then will bigger brakes improve braking distances.

[Stang70Fastback]

I think there is theoretical truth to what he is saying... but we are talking a VERY minor difference in stopping distance as a result of the pads being fully clamped to the rotor a few milliseconds sooner. We're talking SLAMMING on the brakes here. It really is a handful of milliseconds. There are way too many other variables that come into play for that to translate into anything demonstrable in the real world. From tire conditions, to road conditions, to vehicle load, etc...

My understanding is that fixed calipers do offer improved pedal feedback over floating calipers due to the differences he pointed out, which would suggest a more direct connection, and therefore quicker pad application, but I'm not convinced you could truly demonstrate a difference in braking distance between a similarly-sized floating vs. fixed caliper unless you did a literal laboratory experiment. And even then I'd be surprised if it was anything meaningful.

[churchx]

If i keep thinking theoretically about this, then imho "locking up sooner" due "slamming" with pads or brake it with higher friction & bigger initial bite will worsen braking distance of such emergency braking. My line of thought goes that the quicker that slamming/locking happens, the less car has time for mass transfer to front tires, that do most of braking in most cases and which brake bias is usually designed to work with - thus yet unloaded front wheels may lock sooner, abs sooner will have to delock them .. and imho brake distance may increase. On twins, that are relatively lower and on a bit less soft springs then generic family cars or SUVs mass transfer/front tires loading may happen sooner with less time lag, but it still is not immediate. It's all hair splitting though.

[Stang70Fastback]

Originally Posted by churchx

If i keep thinking theoretically about this, then imho "locking up sooner" due "slamming" will worsen braking distance. My line of thought goes that the quicker that slamming/locking happens, the less car has time for mass transfer to front tires, that do most of braking in most cases and which brake bias is usually designed to work with - thus yet unloaded front wheels may lock sooner, abs sooner will delock them .. and imho brake distance may increase. It's all hair splitting though.

I think you're probably right. That's why it's all a pointless exercise. These nuances are all outweighed by the big factors that are road, tire, pad compound, as everyone has already pointed out. I just wanted to throw him a bone. I agree that there is probably some theoretical, and measurable benefit to a fixed vs. floating caliper. My intuition just tells me that it's probably insignificant in the real world, and only truly measurable in a laboratory setting where you can better control all of the other variables.

Just a guess, though! I could be COMPLETELY wrong.

[Spuds]

Originally Posted by Stang70Fastback

Just a guess, though! I could be COMPLETELY wrong.

It's the internet, you are always completely wrong.